added unawaited function for devicelab and turned on unawaited_futures linter (#82833)

dev/devicelab/analysis_options.yaml

+include: ../../analysis_options.yaml
+
+linter:
+  rules:
+    - unawaited_futures

dev/devicelab/bin/run.dart

@@ -6,6 +6,7 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/ab.dart';
 import 'package:flutter_devicelab/framework/manifest.dart';
 import 'package:flutter_devicelab/framework/runner.dart';
@@ -183,7 +184,7 @@ Future<void> _runABTest() async {
   abTest.finalize();
 
   final File jsonFile = _uniqueFile(args['ab-result-file'] as String ?? 'ABresults#.json');
-  jsonFile.writeAsString(const JsonEncoder.withIndent('  ').convert(abTest.jsonMap));
+  unawaited(jsonFile.writeAsString(const JsonEncoder.withIndent('  ').convert(abTest.jsonMap)));
 
   if (!silent) {
     section('Raw results');

dev/devicelab/bin/tasks/build_mode_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -38,9 +39,9 @@ Future<String> runFlutterAndQuit(List<String> args, Device device) async {
       stderr.add(line);
     },
   );
-  run.exitCode.then<void>((int exitCode) {
+  unawaited(run.exitCode.then<void>((int exitCode) {
     runExitCode = exitCode;
-  });
+  }));
   await Future.any<dynamic>(<Future<dynamic>>[ready.future, run.exitCode]);
   if (runExitCode != null) {
     throw 'Failed to run test app; runner unexpected exited, with exit code $runExitCode.';

dev/devicelab/bin/tasks/flutter_attach_test_fuchsia.dart

@@ -7,6 +7,7 @@ import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -202,7 +203,7 @@ void main() {
 
         section('Hot reload');
         runProcess.stdin.write('r');
-        runProcess.stdin.flush();
+        unawaited(runProcess.stdin.flush());
         await eventOrExit(reloadedCompleter.future);
 
         section('Waiting for Dart VM');
@@ -212,7 +213,7 @@ void main() {
         section('Quitting flutter run');
 
         runProcess.stdin.write('q');
-        runProcess.stdin.flush();
+        unawaited(runProcess.stdin.flush());
 
         final int runExitCode = await runProcess.exitCode;
         if (runExitCode != 0 || runStderr.isNotEmpty) {

dev/devicelab/bin/tasks/flutter_engine_group_performance.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -106,5 +107,5 @@ Future<TaskResult> _doTest() async {
 }
 
 Future<void> main() async {
-  task(_doTest);
+  unawaited(task(_doTest));
 }

dev/devicelab/bin/tasks/flutter_run_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -70,7 +71,7 @@ Future<TaskResult> createFlutterRunTask() async {
       }
     });
     await finished.future.timeout(const Duration(minutes: 1));
-    subscription.cancel();
+    unawaited(subscription.cancel());
     run.kill();
   });
   return passedTest && failedTest && skippedTest && finishedMessage && printMessage && writelnMessage

dev/devicelab/bin/tasks/gradle_desugar_classes_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/apk_utils.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -15,7 +16,7 @@ Future<void> main() async {
     try {
       await runProjectTest((FlutterProject flutterProject) async {
         section('APK contains plugin classes');
-        flutterProject.addPlugin('google_maps_flutter', value: '^1.0.10');
+        unawaited(flutterProject.addPlugin('google_maps_flutter', value: '^1.0.10'));
 
         await inDirectory(flutterProject.rootPath, () async {
           await flutter('build', options: <String>[

dev/devicelab/bin/tasks/gradle_plugin_light_apk_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/apk_utils.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -217,7 +218,8 @@ Future<void> main() async {
         });
 
         section('Configure');
-        project.addPlugin('plugin_under_test', value: '$platformLineSep    path: ${pluginDir.path}');
+        unawaited(project.addPlugin('plugin_under_test',
+            value: '$platformLineSep    path: ${pluginDir.path}'));
         await project.addCustomBuildType('local', initWith: 'debug');
         await project.getPackages();
 

dev/devicelab/bin/tasks/ios_app_with_extensions_test.dart

@@ -5,6 +5,7 @@
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/ios.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -80,7 +81,7 @@ Future<void> main() async {
         'EFQRCode.framework',
         'EFQRCode',
       );
-      _checkWatchExtensionFrameworkArchs(watchExtensionFrameworkPath);
+      unawaited(_checkWatchExtensionFrameworkArchs(watchExtensionFrameworkPath));
 
       section('Clean build');
 
@@ -100,7 +101,7 @@ Future<void> main() async {
       checkDirectoryExists(appBundle);
       await _checkFlutterFrameworkArchs(appFrameworkPath, isSimulator: false);
       await _checkFlutterFrameworkArchs(flutterFrameworkPath, isSimulator: false);
-      _checkWatchExtensionFrameworkArchs(watchExtensionFrameworkPath);
+      unawaited(_checkWatchExtensionFrameworkArchs(watchExtensionFrameworkPath));
 
       section('Clean build');
 

dev/devicelab/bin/tasks/ios_content_validation_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/apk_utils.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -53,7 +54,7 @@ Future<void> main() async {
           'Flutter',
         );
         // Exits 0 only if codesigned.
-        eval('xcrun', <String>['codesign', '--verify', flutterFramework]);
+        unawaited(eval('xcrun', <String>['codesign', '--verify', flutterFramework]));
 
         final String appFramework = path.join(
           appBundle.path,
@@ -61,7 +62,7 @@ Future<void> main() async {
           'App.framework',
           'App',
         );
-        eval('xcrun', <String>['codesign', '--verify', appFramework]);
+        unawaited(eval('xcrun', <String>['codesign', '--verify', appFramework]));
       });
 
       return TaskResult.success(null);

dev/devicelab/bin/tasks/module_test_ios.dart

@@ -6,6 +6,7 @@ import 'dart:convert';
 import 'dart:io';
 import 'dart:typed_data';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/host_agent.dart';
 import 'package:flutter_devicelab/framework/ios.dart';
@@ -464,7 +465,7 @@ Future<void> main() async {
     } catch (e) {
       return TaskResult.failure(e.toString());
     } finally {
-      removeIOSimulator(simulatorDeviceId);
+      unawaited(removeIOSimulator(simulatorDeviceId));
       rmTree(tempDir);
     }
   });

dev/devicelab/bin/tasks/routing_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/host_agent.dart';
@@ -68,7 +69,7 @@ void main() {
         .listen((String line) {
           stderr.writeln('run:stderr: $line');
         });
-      run.exitCode.then<void>((int exitCode) { ok = false; });
+      unawaited(run.exitCode.then<void>((int exitCode) { ok = false; }));
       await Future.any<dynamic>(<Future<dynamic>>[ ready.future, run.exitCode ]);
       if (!ok)
         throw 'Failed to run test app.';

dev/devicelab/bin/tasks/run_release_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -79,7 +80,7 @@ void main() {
           print('run:stderr: $line');
           stderr.add(line);
         });
-      run.exitCode.then<void>((int exitCode) { runExitCode = exitCode; });
+      unawaited(run.exitCode.then<void>((int exitCode) { runExitCode = exitCode; }));
       await Future.any<dynamic>(<Future<dynamic>>[ ready.future, run.exitCode ]);
       if (runExitCode != null) {
         throw 'Failed to run test app; runner unexpected exited, with exit code $runExitCode.';

dev/devicelab/bin/tasks/service_extensions_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -50,7 +51,7 @@ void main() {
           .listen((String line) {
         stderr.writeln('run:stderr: $line');
       });
-      run.exitCode.then<void>((int exitCode) { ok = false; });
+      unawaited(run.exitCode.then<void>((int exitCode) { ok = false; }));
       await Future.any<dynamic>(<Future<dynamic>>[ ready.future, run.exitCode ]);
       if (!ok)
         throw 'Failed to run test app.';
@@ -101,7 +102,7 @@ void main() {
 
       final Future<Event> navigationFuture = navigationEvents.first;
       // This tap triggers a navigation event.
-      device.tap(100, 200);
+      unawaited(device.tap(100, 200));
 
       final Event navigationEvent = await navigationFuture;
       // validate the fields

dev/devicelab/bin/test_runner.dart

@@ -8,6 +8,7 @@ import 'package:args/command_runner.dart';
 
 import 'package:flutter_devicelab/command/test.dart';
 import 'package:flutter_devicelab/command/upload_metrics.dart';
+import 'package:flutter_devicelab/common.dart';
 
 final CommandRunner<void> runner =
     CommandRunner<void>('devicelab_runner', 'DeviceLab test runner for recording performance metrics on applications')
@@ -15,10 +16,10 @@ final CommandRunner<void> runner =
       ..addCommand(UploadMetricsCommand());
 
 Future<void> main(List<String> rawArgs) async {
-  runner.run(rawArgs).catchError((dynamic error) {
+  unawaited(runner.run(rawArgs).catchError((dynamic error) {
     stderr.writeln('$error\n');
     stderr.writeln('Usage:\n');
     stderr.writeln(runner.usage);
     exit(64); // Exit code 64 indicates a usage error.
-  });
+  }));
 }

dev/devicelab/lib/common.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Indicates to the linter that the given future is intentionally not awaited.
+///
+/// Has the same functionality as `unawaited` from `package:pedantic`.
+///
+/// In an async context, it is normally expected than all Futures are awaited,
+/// and that is the basis of the lint unawaited_futures which is turned on for
+/// the flutter_tools package. However, there are times where one or more
+/// futures are intentionally not awaited. This function may be used to ignore a
+/// particular future. It silences the unawaited_futures lint.
+void unawaited(Future<void> future) { }

dev/devicelab/lib/framework/adb.dart

@@ -7,6 +7,7 @@ import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
 
@@ -591,13 +592,13 @@ class AndroidDevice extends Device {
           .listen((String line) {
             print('adb logcat stderr: $line');
           }, onDone: () { stderrDone.complete(); });
-        process.exitCode.then<void>((int exitCode) {
+        unawaited(process.exitCode.then<void>((int exitCode) {
           print('adb logcat process terminated with exit code $exitCode');
           if (!aborted) {
             stream.addError(BuildFailedError('adb logcat failed with exit code $exitCode.\n'));
             processDone.complete();
           }
-        });
+        }));
         await Future.any<dynamic>(<Future<dynamic>>[
           Future.wait<void>(<Future<void>>[
             stdoutDone.future,

dev/devicelab/lib/framework/browser.dart

@@ -7,6 +7,7 @@ import 'dart:convert' show json, utf8, LineSplitter, JsonEncoder;
 import 'dart:io' as io;
 import 'dart:math' as math;
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
@@ -625,9 +626,9 @@ Future<io.Process> _spawnChromiumProcess(String executable, List<String> args, {
     // A precaution that avoids accumulating browser processes, in case the
     // glibc bug doesn't cause the browser to quit and we keep looping and
     // launching more processes.
-    process.exitCode.timeout(const Duration(seconds: 1), onTimeout: () {
+    unawaited(process.exitCode.timeout(const Duration(seconds: 1), onTimeout: () {
       process.kill();
       return null;
-    });
+    }));
   }
 }

dev/devicelab/lib/framework/runner.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:meta/meta.dart';
 import 'package:vm_service/vm_service.dart';
 
@@ -103,9 +104,9 @@ Future<TaskResult> runTask(
 
   bool runnerFinished = false;
 
-  runner.exitCode.whenComplete(() {
+  unawaited(runner.exitCode.whenComplete(() {
     runnerFinished = true;
-  });
+  }));
 
   final Completer<Uri> uri = Completer<Uri>();
 

dev/devicelab/lib/framework/utils.dart

@@ -7,6 +7,7 @@ import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/adb.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
@@ -291,10 +292,10 @@ Future<Process> startProcess(
   final ProcessInfo processInfo = ProcessInfo(command, process);
   _runningProcesses.add(processInfo);
 
-  process.exitCode.then<void>((int exitCode) {
+  unawaited(process.exitCode.then<void>((int exitCode) {
     print('"$executable" exit code: $exitCode');
     _runningProcesses.remove(processInfo);
-  });
+  }));
 
   return process;
 }

dev/devicelab/lib/tasks/build_test_task.dart

@@ -5,6 +5,7 @@
 import 'dart:io';
 
 import 'package:args/args.dart';
+import 'package:flutter_devicelab/common.dart';
 
 import '../framework/adb.dart';
 import '../framework/task_result.dart';
@@ -106,7 +107,7 @@ abstract class BuildTestTask {
     }
 
     if (!testOnly) {
-      build();
+      unawaited(build());
     }
 
     if (buildOnly) {

dev/devicelab/lib/tasks/dart_plugin_registry_tests.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
@@ -168,7 +169,7 @@ class PluginPlatformInterfaceMacOS {
         section('Wait for registry execution after hot restart');
         await registryExecutedCompleter.future;
 
-        subscription.cancel();
+        unawaited(subscription.cancel());
         run.kill();
       });
       return TaskResult.success(null);

dev/devicelab/lib/tasks/web_benchmarks.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert' show json;
 import 'dart:io' as io;
 
+import 'package:flutter_devicelab/common.dart';
 import 'package:flutter_devicelab/framework/browser.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
@@ -58,7 +59,7 @@ Future<TaskResult> runWebBenchmark({ @required bool useCanvasKit }) async {
               'Requested to run bechmark ${benchmarkIterator.current}, but '
               'got results for $benchmarkName.',
             ));
-            server.close();
+            unawaited(server.close());
           }
 
           // Trace data is null when the benchmark is not frame-based, such as RawRecorder.
@@ -80,7 +81,7 @@ Future<TaskResult> runWebBenchmark({ @required bool useCanvasKit }) async {
           return Response.ok('Stopped performance tracing');
         } else if (request.requestedUri.path.endsWith('/on-error')) {
           final Map<String, dynamic> errorDetails = json.decode(await request.readAsString()) as Map<String, dynamic>;
-          server.close();
+          unawaited(server.close());
           // Keep the stack trace as a string. It's thrown in the browser, not this Dart VM.
           profileData.completeError('${errorDetails['error']}\n${errorDetails['stackTrace']}');
           return Response.ok('');
@@ -183,7 +184,7 @@ Future<TaskResult> runWebBenchmark({ @required bool useCanvasKit }) async {
       }
       return TaskResult.success(taskResult, benchmarkScoreKeys: benchmarkScoreKeys);
     } finally {
-      server?.close();
+      unawaited(server?.close());
       chrome?.stop();
     }
   });